Structure for conveying a fluid at high temperature



July 14, 1953 R, Pom 2,645,435

STRUCTURE FOR CONVEYING A FLUID AT HIGH-TEMPERATURE Filed July 26, 1949 J0; '9' INVENTUR.

ROBERT POUI T ATTDRNE vs Patented July 14,1953

STRUCTURE FOR CONVEYING A FLUID AT HIGH TEMPERATURE Robert Pouit, Lyon, France, assignor to .Societe Industrielle Generalede Mecanique Appliquee (S. I. G. M. A.), Villeurb of France anne, France, a society Original application April 9, 1947, Serial No. 740,327. Divided and this application July 26, 1940, Serial No. 106,907

The present invention relates to structures for conveying a fluid at high temperature and in particular a structure the outer wall of which is of aerofoil cross section, and constitutes for instance a rotary wing blade propelled "by the reaction of said fluid expelled through a nozzle at the tip of said blade.

This application is a division of my co-pending application S. N. 740,327 filed April 9, 1947 which has matured into Patent No. 2,590,457 granted March 25, 1952. c

The object of the invention is to provide a device of this kind which is better adapted ,to meet the requirements of practice than those used up to this time.

According to my invention, such a structure includes an inner wall at least substantially parallel to said outer wall at a small distance therefrom, forming an inner conduit for said fluid and an undulated partition in the interval between said two walls having its ridges running in the longitudinal direction alternately along one and the other of said walls, so as to form a multiplicity of tubular ducts, air or another fluid at a temperature lower than that of said first mentioned fluid being preferably circulated through at least some of said tubular ducts and in particular those a portion of the surface of which is constituted by the inner wall. I

According to still another feature of my invention, a structure as just above mentioned is constituted by two half-shells, forming respectively the upper and lower portions of said structure and assembled together along the leading and trailing edges thereof.

Preferred embodiments of my invention will be hereinafter described with reference to the accompanying drawings, given merely by way of example and in which:-

Fig, 1 diagrammatically shows, in cross section, an aerodynamic wing blade constituting a structure for conveying a fluid at high temperature according to the invention;

Fig. 2 is a plan view, partly in section, of a rotary wing blade of the kind shown by Fig. 1, shown on a smaller scale; Figs. 3 to 5 are sectional views ofconstructional details of a structure according to the invention.

In the following specification, I will describe examples of structures for conveying a fluid at high temperature constituted by aerodynamic elements and in particular rotary wings.

According to my invention, the hot fluid conveying structure includes an inner wall and an outer wall, thus defining an inner conduit and and an outer conduit, the hot fluid being intended to now through the inner conduit. In order to 2 Claims. (01. 244- reduce to a minimum the losses of pressure in the inner conduit, this conduit is given a section such that only a small interval is left between the wall of said conduit and the outer wall of the structure (rotary wing or blade in the examples shown). In this interval, I provide a multiplicity of adjoining tubular passages through at least some of which a portion-of a relatively cold stream constituted by air under pressure is caused to flow, advantageously with a velocity ensuring a laminar flow, whereas the hot gases, preferably coming from a combustion chamber and having already expanded in a gas turbine, flow through the inner conduit together with a portion of said stream of air under pressure mixed with said gases.

For instance, the cross-section of this inner conduit I0| is given a shape similar to that of the outer wall of the blade, so as to leave, between the outer surface of conduit IM and the inner surface of blade an interval I03 of small thickness in which I provide an intermediate undulated One may cause a portion of the compressed air stream to. flow through both ducts I05 and I06, but preferably this portion of the air stream flows merely through the inner ducts I06.

In both cases, the volume and therefore the velocity of the air stream flowing through these ducts is chosen to maintain a laminar flow.

In the embodiment shown by Figs. 1 and 2.

the relatively cold stream of air under pressure is caused toflow through the inner ducts I06 which are fed, preferably, from a chamber I01 located close to the inner endof the blade (Fig. 2) and to which air under pressure is delivered through a conduit I08.

In order to determine the amount of air entering-each of ducts I06, I provide, between chamber IN and each of these conduits, a partition provided with a calibrated orifice I09. Ducts I06 open at their outer ends into chamber IIO, located ahead of reaction nozzle I I I and into which the hot mixture of gas and air that has flown through the inner conduit IN is also fed.

Concerning said inner conduit .IOI, which is fed through a-conduit m; it is preferably made of several longitudinal sections slidable with respect to one another to permit longitudinal expansion of the whole. Furthermore, preferably, free tubes ..|11 s.

3 transverse expansion of the wall of said conduit H is permitted by relative sliding oftwo lips i and 7' provided on said wall .over its 'whole length (Fig.1).

When the outer ducts are not fed with air under pressure not used in the manner herein after explained, they may be closediat 'bothends or placed in communication with the surround".

ing atmosphere.

According to another feature of the invention,

like half-shells c and d, forming respectively the upper side and the under side or the wing and these elements being assembled together for instance by external welding along their leading edges (see the assembly shown by Fig. 4) and their trailing edges (see the assembly shown by f Fig. 5). r

J Finally, the profile is completed, concerning the 7 leading edge for instance, by addition of solder the outer ducts I05 are placedin communica tion, on the one hand, through apertures H2,

with the outer side of the wing and on the other hand with a space at a pressureeither.higher'or' lower than atmospheric PIGSSUIBfSO asthusto exert on the friction boundary layer on the outer side of wall H12, a blowing or a suction effect.

' in, through apertures H2, the boundary layer onthe outer surface of wall I02, are obtained through'the suction exerted by the gases issuing from' nozzle ill in an annular chamber H6 which surrounds said nozzle and which communihinges'formed alternately in the rear edge of the 'e and, concerning the trailing edge, by assembly "to the main body of the wing of a trailing edge portionf, this assembly being for instance obtained in any suitable manner such as welding or-riveting or preferably, as'shown by Fig. 5, by

means of longitudinal rods g and h engaged in mainbody a-d of the wing and in the rear end portion f;

Inside a wing element thus constituted, one may dispose a freely expansible conduit '1, either insulated as above indicated or not, or, if the gases are at a temperature which is not too high, use merely wall I [8 as wall of conduit l0], while accepting a certain expansion of the structural elements thereof which may, within certain limits, be absorbedby deformation of undulated Wall lo land'bellows al. I Of course-it is not necessary'to have air. or gas in movement flowing through the ducts formed by the undulated partition between the inner conduitand the external wall.' On the other hand, at leastsome of the above described cates, through calibrated orifices I H, with ducts 7 [05 (as shown in dotted lines in Fig. 2).

'In this case, of course, tubes H3 and chamber l M are not used. In all cases, a good heat insulation between the .inner conduit [0| and the outer wall 182 is ob:

tained, owingtothe provision of ductsll05 and H36 in the interval between saidconduit and said wall; v This heat insulation is practically unafiected by the thermal conductivity of the undulated'par tition 564 which serves to constitute these ducts, even if this undulat'ed Wallis metallic.

However, in order further to reduce the effect features could be applied to a fixed wing or a wing operated with a reciprocating motion and even, more generally, to any fixed or movable conduit for conveying fluids at high temperature.

In a general manner, while I have, in the above description, disclosed what I deem'to be practical and efficient embodiments of my invention, it should be well understoodthat I do not wish to" be limited thereto as there might be changes made in the arrangement, disposition andfform of the parts without departing from the principle of the present invention as compre-.

of this conductivity, this undulated partition may L be made of a material which is a bad conductor of heat or a layer of an insulating material may be interposed between the wall of conduit in! and the und'ulatedpartition.

. Although it is'not necessary toensure fluidtightness betweenducts 196 and inner conduit IBI since the gases flowing therethrouglr are substantially at the same pressure, I may, in order to improve the resistance of thestructurefstiffen hended within the scope of the accompanying a s,

What I claim is: a ,1,. An aircraft structure which comprises, in combination, a hollow wing having a skin of airfoil cross section, a continuous wall inside said wing substantially parallel to said skin running along most of the wing span to form a continuous central conduit stopping short of the wing tip the assembly of outer wall I62 and undulatedwall 1 04 by securing the latter, for instance by welding, on the one hand to the outer wall and, on the other hand, to an inner metal sheet H8, as shown by Fig. 3. Elements I02 and. I04 may be assembled together by electrical spot welding. Concerning the welding of elements I04 and l l8 together, it may be facilitated by dividing metal sheet I 18 into separate sections such as l I81, H 82, etc. (Fig. 4) 'Each of the edges 11 of the sections of this metal'sheet may be bent (edges shown in dotted lines byFig. 4) for making first the longitudinal welds 12 between partition {04 and the metal sheet sections H81, H82, etc., and finishing the assembly by welding of the bent edges together, a's 'sho'wn at an insolid lines.

' Furthermore, it is' advantageous to constitute the wing structure by assembly of two boxwhere said skin forms a hollow chamber, a jet nozzle at the tip of the wing opening from said chamber into the atmosphere, a corrugated partition in the space between said wall and said skin having its corrugations directed spanwise and alternately applied against said skin and said wall to form, between said wall and said skin over the whole periphery of their cross sections, a layer of iluidtight tubular ducts running spanwise and opening into said chamber at the tip of the wing, means for feeding a stream of hot gas -,to the root end of said central conduit, and means for feeding a stream of relatively cool gas to the root end of at least every second tubular duct.

2. An aircraft structure which comprises, in combination, a hollow wing having a skin of airfoil cross section, a continuous wall inside said wing substantially parallel to said skin running along most of the wing span to forma continuous centralconduit stopping short of the wing tip where said skin forms a hollow chamber, a jet nozzle at the tip of the wing opening from said chamber into the atmosphere, a corrugated partition in the space between said wall and said skin having its corrugations directed spanwise and a1- ternately applied against said skin and said wall to form, between said wall and said skin over the whole periphery of their cross sections, a layer of fluidtight tubular ducts running spanwise and opening into said chamber at the tip of the wing, means for feeding a stream of hot gas tothe root end of said central conduit, and meansfor feeding a stream of relatively cool gas to the root end of every tubular duct a portion of thewall of which is constituted by a portion of said innerwall. 1

ROBERT POUIT.

References Cited in the file of this patent UNITED STATES PATENTS Number Number Name 1 Date Dewey Aug. 30, 1887 Stout Jan. 26, 1932 Markey Dec. 13, 1932 Busselmeier Jan. 16, 1940 Wagner May 13, 1941 Watter July 9, 1946 Pecker Nov. 5, 1946 Sikorsky May 10, 1949 Stalker July 25, 1950 Palmatier June 12, 1951 FOREIGN PATENTS Country Date Great Britain Mar. 15, 1940 

